1. Field of the Invention
The present invention relates to an ophthalmic apparatus used by ophthalmologists or opticians.
2. Description of Related Art
As a known ophthalmic apparatus, there is an apparatus for obtaining distribution of corneal radius of curvature covering a wide area of a cornea using an image of placido rings formed on the cornea of the eye in order to visualize corneal topography. Also, there is an apparatus suggested, for example, in U.S. Pat. No. 5,907,388, for obtaining distribution of eye refractive power at a number of portions of the eye. Further, an apparatus suggested, for example, in U.S. Pat. No. 6,033,075 obtains data on an amount of cornea to be ablated based on these thus obtained data on distribution, and use the data in corneal refractive surgery.
However, in the case where plural data measured at different times are used to obtain new data or to examine the relation between each measurement data, each measurement data needs to be consistent in their two-dimensional positional relationship. If not, accurate results may not be obtained, and comparisons between them may not be easy.
The present invention has been made in view of the above circumstances and has an object to overcome the above problems and to provide an ophthalmic apparatus capable of aligning the positional relationship of plural measurement data measured at different times with each other so that comparisons and analyses of each measurement data may be carried out easily and accurately.
Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, an ophthalmic apparatus comprising a first input unit with which plural measurement data concerning an eye to be examined are inputted, a second input unit with which images of the eye including an anterior eye segment are inputted, each of the image is photographed at the time of measuring each of the inputted measurement data, and a calculation and control unit which detects and corrects two-dimensional displacement or deviation between each of the measurement data based on each of the inputted images of the eye.
In another aspect of the present invention, an ophthalmic apparatus comprising a corneal shape measurement unit which measures distribution of corneal radius of curvature of an eye to be examined, an eye refractive power measurement unit which measures distribution of eye refractive power of the eye, an alignment unit which detects an alignment state of the ophthalmic apparatus relative to the eye, and a calculation and control unit which detects and corrects two-dimensional displacement or deviation between each of data on the measured distribution with reference to at least an image of the eye including an anterior eye segment photographed by either the first photographing element or the second photographing element at the time of each measurement. The corneal shape measurement unit has an optical system for projecting a first measurement target onto a cornea of the eye, and an optical system provided with a first photographing element for detecting an image of the first measurement target formed on the cornea. The eye refractive power measurement unit has an optical system for projecting a second measurement target onto a fundus of the eye, and an optical system for detecting an image of the second measurement target formed on the fundus. The alignment unit has an optical system for projecting an alignment target onto the cornea of the eye, and an optical system provided with a second photographing element for photographing an image of the alignment target formed on the cornea.
In yet another aspect of the present invention, an ophthalmic apparatus comprising a first input unit with which plural measurement data concerning an eye to be examined are inputted, a second input unit with which displacement or deviation of the eye relative to a predetermined reference position at the time of measuring each of the inputted measurement data is inputted, and a calculation and control unit which detects and corrects two-dimensional displacement or deviation between each of the measurement data with reference to each of the inputted displacement.